California’s coastline is known for its mild weather, making the threat of tropical cyclones seem rare. While the state is mostly spared the direct experience of hurricane landfalls common to the Gulf or Atlantic Coasts, it has certainly felt the devastating effects of these systems. Understanding how a storm is defined is the first step in counting the true impact tropical weather has had on the state. This analysis clarifies the distinction between a true hurricane and the tropical systems that have historically reached the coast, providing a historical count and explaining the powerful meteorological forces that serve as California’s natural defense.
Defining a “Hit”: Tropical Cyclones and California’s Coast
The term “tropical cyclone” is a general classification for a rotating, organized system of clouds and thunderstorms that forms over warm, tropical waters. A tropical cyclone is named a “hurricane” only when its maximum sustained winds reach 74 miles per hour or higher, which is equivalent to a Category 1 storm on the Saffir-Simpson Hurricane Wind Scale. If the sustained wind speed is between 39 and 73 miles per hour, the system is classified as a tropical storm.
For California, a “hit” almost never involves a hurricane maintaining its strength to landfall. The systems that reach the state are typically weakened tropical storms, tropical depressions, or post-tropical remnants. These systems still carry immense amounts of tropical moisture, which can lead to flash flooding and significant wind damage. The impact is usually measured not by the wind speed at landfall, but by the widespread rainfall, high surf, and coastal flooding it generates.
True hurricane landfalls, where a Category 1 storm or stronger crosses the coastline, are essentially nonexistent in the modern record. The primary danger to California from tropical weather is not the swirling vortex of a major hurricane, but the massive deluge of water delivered by a diminished system. Therefore, the historical count focuses on all tropical systems that have maintained sufficient strength to cause significant damage or bring tropical storm-force winds to the coast.
The Historical Count of Significant Tropical Storm Impacts
The number of times a tropical cyclone has directly impacted California as a strong system is exceptionally small. The only tropical cyclone in the modern record to make landfall in California as a tropical storm was the Long Beach Tropical Storm in September 1939. Also known as El Cordonazo, this storm brought winds gusting up to 65 miles per hour and dumped five inches of rain in 24 hours on parts of Los Angeles County. The storm’s unexpected arrival caused widespread flooding and resulted in the deaths of 93 people, mostly at sea.
Before the era of satellite tracking, the 1858 San Diego hurricane struck the region. Historical reconstructions suggest this storm produced hurricane-force winds, with gusts up to 75 miles per hour, making it the only known tropical cyclone to produce hurricane-force winds along the California coast. Although the center of the storm may have remained offshore, it caused extensive property damage in San Diego, where many homes lost their roofs and fences were destroyed.
Since record-keeping began, only a few other tropical systems have maintained tropical storm status while tracking over California. A notable recent example is Hurricane Hilary in August 2023, which was the first time the National Hurricane Center issued a tropical storm warning for Southern California. Hilary made landfall in Mexico’s Baja California Peninsula as a tropical storm, but maintained that status as it crossed into Southern California, bringing historic rainfall and flash flooding. Other systems, like Tropical Storm Nora (1997) and the remnants of Hurricane Kathleen (1976), have brought gale-force winds and devastating precipitation to the state.
Meteorological Barriers That Protect California
The infrequency of these events is the result of two powerful meteorological barriers that protect the West Coast. The most significant factor is the California Current, a cold ocean current that flows southward along the Pacific coastline. This current keeps the sea surface temperatures off Southern California cooler than the 80°F threshold required to sustain a hurricane.
As a tropical cyclone tracks north from its formation zone near Mexico, it encounters this rapidly cooling water, which acts like a massive energy-sapping cold front. Without the warm, moist air rising from the ocean surface to fuel its core, the storm rapidly loses its intensity and organization. The system quickly weakens from a hurricane to a tropical storm, and then often to a tropical depression or post-tropical remnant.
The second major barrier involves prevailing atmospheric steering patterns, specifically a persistent high-pressure system known as the subtropical ridge. This ridge typically sits over the eastern Pacific, creating wind patterns that steer most developing storms away from the coast, pushing them to the west and out into the open ocean. Only when this high-pressure system weakens or shifts eastward, as happened with Hurricane Hilary in 2023, can a tropical system find a clear path to track northward and affect California.